Starred Rupert Everett brilliantly playing two parts - the deliciously seditious headmistress and her brother.
Stephen Fry, Colin Firth and....a certain Russell Brand co-star.
The St. Trinians "Fritton's Gold" sequel to that was/is even better - with a subversive green sub-theme thrown in.
Here're Girls Aloud belting it out in ripped, mocked-to-bits school uniforms:
Interview with the Aloud gals re St.Trinians: